Additons, alterations to, or repairs on existing systems shall not cause a system to become

The advantage of using a pump-down control on a commercial refrigeration system is to:

A solenoid is a coil of wire that, when energized, creates a magnetic field which causes some action to occur in an electric device.  Solenoid coils are NOT a component part of which of the following electric devices?

The type of current that controls the contacts in the current relay is:

 Louvers and grills shall have a net free area of ____ for wood and ____ for metal

What type of vent is designed specifically for category I gas appliances?

Before working with chemical solvents, oils and refrigerants, the technician should review:

Heat that travels within a fluid such as air or water by means of currents would be defined as what type of heat transfer?

What is the area in square feet of a 15 inch round duct?

The input Btu rating of a gas furnace is 105,000 Btu. The gas heating value of one cubic foot of natural gas is 1030 btu. Calculate the cubic feet per hour of gas the furnace requires to operate. (Rounded up to whole numbers)